It is well known that adding a tetrafluoroethylene polymer, particularly polytetrafluoroethylene (PTFE), to other polymers to form a blend often improves the wear properties of such other polymers. This characteristic is believed true of thermotropic LCPs, which by themselves are generally thought to have relatively poor wear properties. However, even when blended with tetrafluoroethylene polymers, the wear properties of LCPs could still be improved further. It has been found that when an LCP having a relatively high Tg (i.e., greater than about 140.degree. C.) is blended with a tetrafluoroethylene polymer, the resultant blend has superior wear characteristics as compared to a blend made from an LCP having a lower Tg. It has further been found that the higher the Tg of the LCP in the blend, the higher the use temperature of the blend and the better the wear properties obtained by the blend, even under heavy frictional load.
U.S. Pat. Nos. 4,417,020 and 4,429,078 describe blends of LCPs with tetrafluoroethylene polymers. No specific mention is made in these references of the importance of the Tg of the LCP in these blends.
G. S. O'Brien et al., Compalloy '91, Proceedings of the Fourth International Congress on Compatibilizers and Reactive Polymer Alloying, New Orleans, Jan. 30-Feb. 1, 1991, p. 131-148, describes the wear properties of PTFE-LCP blends. The Tgs of the LCPs are not mentioned therein.